The ongoing patent war between Apple and Samsung took an interesting turn on Friday as a poorly redacted document was accidentally filed that revealed details the companies had tried to keep secret.

The document was filed as part of US District Judge Lucy Koh’s ruling that denied Apple’s request for an injunction on sales of Samsung’s Galaxy devices. The document that was posted online by Judge Koh’s office left clear certain details that she had intended to black out, apparently at the company’s request. The error was quickly caught and the document sealed, but not before several news organizations managed to obtain a copy. A correctly redacted version appeared later in the day.

The document contains references to market research conducted by Apple which shows that consumers are unlikely confuse Samsung’s Galaxy phones and tablets with Apple’s own iPhone and iPad. The foundation of the suit, which was filed in April and quickly spread to ten countries, is that Samsung’s products copy the design and interface of Apple’s devices too closely, such that they constitute a violation of Apple’s patents.

Samsung’s Galaxy Tab 10.1, in particular, is generally seen as a major competitor for Apple’s iPad, and one of the best of the myriad Android tablets available. That fact may be at least part of why Apple has pursued this case so vigorously, rather than simply setting up a deal whereby Samsung licensed the relevent patents from Apple. Last week The Verge reported that Apple had in fact licensed one such patent to IBM and Nokia, but not Samsung.

In most places the legal battle has gone largely in Apple’s favor. Most recently, we reported that Apple got a injunction that had been overturned in Australia reinstituted until its appeal could be heard.